Jasbird writes
Unless Glyphosate can be used in this kind of weather it is no good to
me.

I want to kill off my weeds before I dig the ground over because I
don't like having to hoe tough weeds with deep roots (which have a
tendency to re-grow even when dug over - especially couch grass.

I'm not sure anything is going to be much good to you then ;-)
A weedkiller which works on the active growth is not going to be of use
at the moment, and anything which prevents re-growth will have adverse
effects on your veg.

What have you done in previous years? - hand-picked the couch roots as
you dig?
--
Kay